Ratchet type rotary impact tool



Dec. 1, 1959 E. CRICK RATCHET TYPE ROTARY IMPACT TOOL Filed Dec. 9, 1958 IHII.

' INVENTOR. a/men a. 6 m4:

BY v 9 flrfaiA/' s United States Patent RATCHET TYPE ROTARY IMPACT TOOL Leonard E. Crick, Hastings, Nebr.

Application December 9, 1958, Serial No. 779,261 8 Claims. c1. 8152.3)

(Granted under Title 35, US. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to me of any royalty thereon.

The present invention relates to a device for the removal of embedded screws and other impacted or frozen fastening elements and, more particularly, to a tool for removing impacted flush head screws from aircraft wings and the like.

In usual screw removing operations, it is often necessary to bore a hole or groove in the head of the screw for receiving a removal tool, the removal of deeply embedded screws being a difficult and time consuming operation.

The object of the present invention is to provide a tool having hammer impact and circular motion for withdrawing the screw and in most cases removes the necessity for boring the hole above mentioned.

A further object of the invention is the provision of an easily constructed and easily used tool, simple to manufacture and to operate, for the removal of embedded or frozen screws, particularly in aircraft wings.

A further object of the invention is the provision of a time saving tool which removes embedded or frozen screws in a matter of minutes when previously hours were required for the operation.

In the drawing, Figure l is an exploded view, showing elements of the tool in-longitudinal cross section, and a portion in elevation.

Figure 2 is a fragmentary view of the assembled-tool partly in elevation and partly in cross section.

Referring more in detail to the drawing, a barrel 10 is received in a sleeve 12 and secured to it in a rigid and nonrotating manner by means of the screw 14. On one end the barrel 10 is provided with a reduced diameter shank 16 provided with an annular recess 18. At the opposite end of the barrel portion 10 there is provided a concentric cylindrical axially extending recess 20, and an axially extending and eccentrically positioned recess 22. The barrel portion 10 is also provided with a pair of slots 24, located on its circumferential periphery and diametrically opposite to each other. The slots 24 are diagonal, extending in a direction which is angular to the line of the axis of the barrel 10. The diagonal slots 24 are arranged in crossed angular relationship to each other with a purpose in view which will be later described.

A pin 26 and a compression spring 28 are insertable in the cylindrical recess 22. The pin 26 has an angularly cut end portion 30 formed to function as a ratchet tooth engaging ratchet teeth or grooves 32 formed in the end of a cylindrical head 34. The element 34 is of such outside circumference as to fit within the sleeve 12 and the ratchet tooth or pin 26 operates to lock the elements 10 and 34 against relative rotation in one direction and allow rotation in the other direction, i.e., when the movement is counterclockwise (looking in the direction of the arrow A) the elements 10 and 34 are locked, and when the movement is clockwise, relative rotation occurs. The head 34 is provided with an axially and forwardly extending cylindrical recessed portion 36 and a rearwardly extending stud portion 38. The stud or shank portion 38 is provided with internal screw threads 40 for engagement with a rod or shaft 42 and receives the hammer blows of a hammer head, later described. Element 44 serves as a handle or other support means. A radially extending screw-threaded opening 45 accommodates the flush head screw 46, which engages in the annular recess 18 in the shank 16, providing relatively rotative engagement between the barrel portion 10 and the head 34. i

In assembling, the element 34 is slipped into the sleeve 10 and thereafter the screw 46 is inserted in the screw threaded opening 45 extending within the interior periphery of the recess 36 and engageable within the annular recess 18 in the shank portion 16, thereby securing the element 34 to the stud 16, in a manner to allow relative rotation. It will be seen that the pin 26 resiliently engages the ratchet teeth or grooves 32.

As previously stated, the shaft 42 threadedly engages the stud 38, and supports an impact hammer head 52 which is slidable thereon.

A tool holding element 60 is of such diameter as to be slidable within the recess 20 and has cylindrical bores 62 and 64 located on its respective opposite ends. Openings 66 are radially positioned in the element 60 in diametrically opposed relationship. Impact pins 70 are insertable in each of the slots 24 and the openings 66. It is to be understood that the slots 24 and pins 70 and recesses 66 are duplications of each other on diametrically opposite sides of the tool. A compression spring 68 is accommodated in the recesses 62 and 20 and biases the pin 70 to the forward end of the slot 24 so that any compressive movement rotates the element 60 in a counterclockwise direction. A screwdriver head 72 may be a Phillips or Allen type or a socket wrench head, or any expedient tool for removal of embedded screws and rusted, frozen or broken bolts. recess 62 by a set screw 74. The tool may also be used for removing broken bolts by drilling a hole in the bolt and using a conventional removal device.

The operation of the device is as follows: When the hammer portion 52 is brought forcefully against the shank member 38, the head 34, the barrel 10 and sleeve 12 are driven forcefully in the direction indicated by the arrow A. The barrel and sleeve are locked by the ratchet pin 26. The pin and slot relationship of the pins 70 and slots 24 cause a rotary movement of the tool holding element 60 in a counterclockwise direction, from the point of view of the operator, i.e., looking in the direction of the arrow A. The shock impact and the rotary movement imparted to the tool 72 in a counterclockwise direction causes the screw or bolt to break loose.

During this operation, the head 34 and barrel 10 have been locked against rotation. The barrel may now be freed from the head, and the sleeve rotated rapidly counterclockwise for completing the withdrawal of the screw after the shock impact and initial rotary movement have jarred it loose.

While the invention is shown and described in connection with one form for illustrative, rather than restricted purposes, it is obvious that changes and modifications may be made by those skilled in the art without departing from the scope and spirit of the invention as defined in the accompanying claims.

I claim:

1. A device for removing embedded screws comprising a sleeve, a barrel element rigidly held in said sleeve, said barrel element being provided with a cylindrical concentric axially positioned bore, a tool carrying element slidingly engageable in said bore, a screw remov- This tool is retained in' ing tool secured in said element and capable of engaging the head of an embedded screw to be removed, a compression spring seated at one end in the bore in said barrel and at the other end in a companion borein said tool holding element, said barrel element and said tool holding element being provided with interengaging diagonal slot and pin connection means, a hammer elementfor moving said barrel portion forward with shock impact, the angle of said pin and slot connection means being in a direction to impel the tool carrying member forward and at the same time impart a counterclockwise motion thereto.

2. In the device according to claim 1, an axially extending, reduced diameter shank on said barrel, a cylindrical head carried partially within said sleeve and rotatably secured to said shank, ratchet engagement means between said head and said barrel to lock said barrel in said head against relative rotation in one direction and allowing relative rotation in the other direction for rapid backing up of the screw after it has been loosened by the defined shock impact and counterclockwise movement.

3. A device for removing embedded screws and other impacted fastening elements comprising a tool for engaging said embedded screw or other fastening element, means for providing simultaneously shock impact and rotary counterclockwise movement to said tool, said shock and rotary movement-providing means comprising a barrel, a tool carrying element slidable in said barrel, said barrel being provided with a diagonal slot, a pin attached to the outer periphery of said tool carrying element and engageable in said diagonal slot, hammer means for imparting shock impact and forward movement to said barrel, said pin and slot connection causing said tool to rotate in a counterclockwise direction for loosening said impacted fastening element.

4. In the device as set forth in claim 3, a rod, said hammer means being slidably mounted on said rod, a head having rigid attachment to said rod, ratchet engagement means between said head and said barrel for locking said rod and said barrel against relative rotation in one direction and allowing relative rotation in the other direction.

5. In the device as set forth in claim 4, a compression spring seated in companion recesses in said barrel and said tool carrying member, the bias of the spring holding said pin at the forward end of said-diagonal slot, so that compressive movement of said spring rotates said tool carrying element in a counterclockwise direction.

6. In the device as set forth in claim 5, ratchet teeth on said head, a ratchet pin seated in an axially extending eccentrically positioned recess in said barrel, a spring located in said recess and imparting resilience to said' ratchet pin, said pin engaging in said ratchet teeth and providing the above defined ratchet engagement between said head and said barrel.

7. An impact rotary screw loosening and removing tool comprising a rod member, an impact hammer slidable on said rod member, a cylindrical head fixed on the end of said rod member for receiving impact blows from said hammer, said head having a central cylindrical recess opening in axial extension of said rod member, a barrel member disposed in concentric rotative relation to said cylindrical head and having a shank portion rotatably seated in said central recess, ratchet means between said barrel and head portions for preventing relative rotation of said barrel in a clockwise direction relative to said cylindrical head, said barrel having a cylindrical axially disposed concentric recess therein opening in axial extension of said shank, and formed with diametrically opposite inclined elongated camming slots intermediate theopposite ends of the recess, both inclining in a diagonal clockwise direction, a cylindrical tool holder axially slidably and rotatably disposed in said last named recess, diametrically opposed impact pin portions projecting from opposite sides of the tool holder into said inclined slots, whereby impact pressure applied, to said tool holder imparts relative movement to said tool holder in a counterclockwise direction, spring means between said tool holder and said barrel for yieldably urging said tool holder away from said barrel, said tool holder having a tool receiving socket formed therein for receiving a tool for interengaging a screw fastener to be loosened and removed by said tool.

8. Apparatus as claimed in claim 7 including a cylindrical sleeve member concentrically enclosing the outer cylindrical surfaces of both barrel and head members, and means securing said sleeve member to the barrel member.

References Cited in the file of this patent UNITED STATES PATENTS 1,776,057 Weibull Sept. 16, 1930 2,507,167 Lemmerman May 9, 1950 2,638,806 Spielman May 19, 1953 2,661,647 Swenson Dec. 8, 1953 2,688,268 Lear Sept. 7, 1954 2,833,173 Aspeek May 6, 1958 2,844,982 Swenson July 29, '1958 FOREIGN PATENTS 686,683 Great Britain Jan. 28, 1953 

